rbe

Overview

The rbe (Report By Exception) node only passes messages through when the monitored value has actually changed. It suppresses duplicate or near-duplicate readings, reducing noise and unnecessary processing. It supports exact value comparison, deadband filtering (ignore changes smaller than a threshold), and narrowband filtering (only pass if the change is within a range).

Properties

Filtering Modes

// Input: 20, 20, 21, 21, 20
// Output: 20,     21,     20
// Exact match comparison

// Bandgap: 0.5
// Input: 20.0, 20.3, 20.6, 20.4
// Output: 20.0,      20.6
// Change must exceed 0.5

// Bandgap: 2.0
// Input: 20.0, 20.5, 25.0, 20.8
// Output: 20.0, 20.5,      20.8
// Blocks changes > 2.0 (spike)

Example: Temperature Change Detection

Only report temperature when it changes by more than 0.5 degrees Celsius, filtering out sensor noise.

// RBE node configuration
{
  "property": "payload.temperature",
  "mode": "deadband",
  "bandgap": 0.5,
  "invert": false
}

// Flow: [Temp Sensor] -> [RBE] -> [Dashboard] -> [Database]
//
// Sensor sends every 5 seconds:
// 22.1 -> PASS (first message always passes)
// 22.2 -> BLOCK (change of 0.1, less than 0.5)
// 22.3 -> BLOCK (change of 0.2, less than 0.5)
// 22.0 -> BLOCK (change of 0.1, less than 0.5)
// 22.7 -> PASS  (change of 0.6, exceeds 0.5)
// 22.8 -> BLOCK (change of 0.1 from last passed)
// 23.3 -> PASS  (change of 0.6, exceeds 0.5)
//
// Result: 70% fewer messages to dashboard and database

Example: State Change Detection for Switches

Only react when a door sensor or switch actually changes state between open and closed.

// RBE node configuration (value mode for exact comparison)
{
  "property": "payload.state",
  "mode": "value",
  "invert": false
}

// Flow: [Door Sensor MQTT] -> [RBE] -> [Automation Logic]
//
// Sensor publishes state every 1 second:
// "closed" -> PASS  (initial state)
// "closed" -> BLOCK (no change)
// "closed" -> BLOCK (no change)
// "open"   -> PASS  (state changed!)
// "open"   -> BLOCK (no change)
// "open"   -> BLOCK (no change)
// "closed" -> PASS  (state changed!)
//
// Without RBE: 60 messages per minute
// With RBE: Only 2-3 messages when state actually changes
//
// Connect output to:
// - Notification node (alert when door opens)
// - Light control (turn on lights when open)
// - Logging (record open/close timestamps)

Common Use Cases